Josephson Clinical Cardiac Electrophysiology

156

■ Josephson’s Clinical Cardiac Electrophysiology

1 2

1 2 3 V1

1 2 3 V1

3 V1

A1

A1

A2

A1

A2

A2

HRA

HRA

HRA

500 A1H1 V1

455 A1H1 V1 A2

615

V1

H1

A2

V2

A1

V2

A2

V2

H2

H1-H2 640

H2

H1-H2 540

H1-H2 500

H2

HBE

HBE

HBE

185

160

205

160

205

160

RB 95

RB 60

60

RB

60

60

300msec

T

T

T

135

S

S

S

S

S

A

B

C

FIGURE 5.16 “Pseudo-supernormal” conduction with intra-His delay resulting in normalization of aberrant interventricular conduction. A to C. Pro gressively premature atrial extrastimuli (A2) are delivered after the eighth paced atrial complex (A1). Discrete His bundle and right bundle branch (RB) potentials are seen with an H-V of 60 msec during this premature complex. A. An A1-A2 of 615 results in an H1-H2 of 640 msec without altering infranodal conduction. B. An A1-A2 of 500 results in an H1-H2 of 540 msec. This is associated with a marked H-RB delay (35 msec) and the development of right bundle branch block (RBBB). C. At a shorter A1-A2 (455 msec) and H1-H2 interval (500 msec), normalization of the QRS complex occurs because of a more marked proximal intra-His delay (H-RB = 75 msec), which allows recovery of the RB.

I

II III

A

A1

A2

1,190

480

HRA

V1

V2

V

A2 H2

A1

H1

H1-H2 510

A H

HBE

S 125

90

40

70

A

FIGURE 5.17 “Pseudo-supernormal” conduction with His-Purkinje system (HPS) delay resulting in normal ization of aberrant interventricular conduction. The basic rhythm in all panels is sinus, with a constant cycle length of 1,190 msec. A premature atrial stimulus (A2) is introduced at progressively shorter coupling inter vals. A. The premature beat is con ducted with a right bundle branch block (RBBB) and left anterior hemi block (axis − 60°) pattern. B. The conducted QRS complex is less ab errant. C. The conducted QRS com plex is virtually identical to the QRS complexes during A1 (drive beats). Despite decreasing H1-H2 intervals, the H2-V2 progressively increases, and normalization of the QRS com plex can be attributed to proximal de lay in the HPS, allowing progressive recovery of the distal area of delay and aberration. See text for discus sion. (Reprinted from Gallagher JJ, Damato AN, Varghese PJ, et al. Al ternative mechanisms of apparent supernormal atrioventricular con duction. Am J Cardiol . 1973;31:362, with permission from Elsevier.)

I

II III

A

A1 470

A2

1,190

HRA

V1

A2 H2

V2

H V

500

A1H1

A

HBE

90

S

125

40

110

B

I

II III

Copyright © 2023 Wolters Kluwer, Inc. Unauthorized reproduction of the content is prohibited. 1,190 A A1 435 A2 HRA

A2

H2

V

A1 V1 H1

V2 H1-H2 480

A H

HBE

90

S 130

40

145

300 msec

T

C